linux-kernel - Re: [PATCH v2 06/10] mm/vmalloc: Handle non-blocking GFP in __vmalloc_area

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Message-ID: <aMt2EUYD75Wqz1p6@MiWiFi-R3L-srv>
Date: Thu, 18 Sep 2025 11:01:37 +0800
From: Baoquan He <bhe@...hat.com>
To: "Uladzislau Rezki (Sony)" <urezki@...il.com>
Cc: linux-mm@...ck.org, Andrew Morton <akpm@...ux-foundation.org>,
	Michal Hocko <mhocko@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>, Michal Hocko <mhocko@...e.com>
Subject: Re: [PATCH v2 06/10] mm/vmalloc: Handle non-blocking GFP in
 __vmalloc_area_node()

On 09/15/25 at 03:40pm, Uladzislau Rezki (Sony) wrote:
> Make __vmalloc_area_node() respect non-blocking GFP masks such
> as GFP_ATOMIC and GFP_NOWAIT.
> 
> - Add memalloc_apply_gfp_scope()/memalloc_restore_scope()
>   helpers to apply a proper scope.
> - Apply memalloc_apply_gfp_scope()/memalloc_restore_scope()
>   around vmap_pages_range() for page table setup.
> - Set "nofail" to false if a non-blocking mask is used, as
>   they are mutually exclusive.
> 
> This is particularly important for page table allocations that
> internally use GFP_PGTABLE_KERNEL, which may sleep unless such
> scope restrictions are applied. For example:
> 
> <snip>
> __pte_alloc_kernel()
>   pte_alloc_one_kernel(&init_mm);
>     pagetable_alloc_noprof(GFP_PGTABLE_KERNEL & ~__GFP_HIGHMEM, 0);
> <snip>
> 
> Note: in most cases, PTE entries are established only up to the
> level required by current vmap space usage, meaning the page tables
> are typically fully populated during the mapping process.
> 
> Acked-by: Michal Hocko <mhocko@...e.com>
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@...il.com>
> ---
>  include/linux/vmalloc.h |  2 ++
>  mm/vmalloc.c            | 52 +++++++++++++++++++++++++++++++++--------
>  2 files changed, 44 insertions(+), 10 deletions(-)

Reviewed-by: Baoquan He <bhe@...hat.com>